Paris is trying to beat New York on the car-congestion problem. Biking is the latest fad here. Gray-haired gentlemen in suits and ties with their briefcases in the baskets in front of them ride through busy streets with aplomb while young women pedaling in high heeled shoes wind their way through stopped traffic as if they had done it all their lives. On weekends, entire families ride together like small armies, causing a near crisis when the stoplight turns red and someone is left behind, usually a child.